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Bioenergy Technology are approved
suppliers and installers of log and pellet boilers, woodchip
and combination boilers with storage and transport solutions
and log and wood pellet stoves. Their products range from 3kW
to 6MW for space heating, process or combined heat and power.
The team has worked successfully on some of the first carbon
neutral biomass, boiler and low carbon heating projects in the
UK, including The Woodland Enterprise Centre, Buchan Park, Sanford
Housing Co-op and Bore Place.

Biomass
and biofuels:

These
are renewable organic fuels from harvested crops -the CO2 released
when energy is generated is balanced by that absorbed during
the growth of the fuel material. Fuels include woody biomass
crops such as coppiced willow, high energy crops such as sugar
cane or maize, or animal waste. Below, Elliott Flynn of Windhager
UK, Suppliers of innovative biomass boilers and solar thermal
systems, explains the thinking behind Biomass.

The Basics of Biomass

Elliott Flynn

Biomass is the generic term
used to describe solid fuels sourced from recently grown material.
Biomass fuels shouldn't be considered to be 'new' or 'alternative'
fuels -in fact they were burnt for fuel thousands of years before
fossil fuels were. When fossil fuels are burnt, they release
long locked-up carbon back into the atmosphere, whereas in the
case of of bio-fuels carbon released when energy is generated
is balanced by that absorbed during the growth of the fuel material.

The term Biomass covers plant material such as miscanthus and
grains as well as woody material such as coppiced willow and
wood pellets, and high energy crops such as sugar cane or maize,
or animal waste.

Above, a Biomass Boiler designed
to accept large bales of material, in this case, straw is used.

The commonest biomass fuel
is wood -although relatively slow growing in comparison to grasses
such as miscanthus, it is an excellent biomass fuel source.
Woody biomass has comparatively high energy density compared
to other biomass fuels. The prevalence of wood processing
operations in existing industries such as construction, transportation,
and furniture which produce large amounts of waste which are
ideal sources of fuel. Rather than paying the costs of
removing waste material, it can be turned into a saleable by
product for wood processors and manufacturers. This is
a major benefit to wood fuels as its does not rely solely on
agricultural production to provide fuel nor does it take up agricultural
land which could be used to produce food.

Most biomass fuels do require some form of processing. Grasses,
woody material and seeds can be milled into pellets. Wood can
be chopped to length and split, chipped or pelletised in order
for it to be burnt. Grasses can also be baled and burnt
whole or be milled into pellets. The production of fuel
pellets is essentially the same as the production of pellets
for animal feeds. The stock material is dried and ground
to produce a dust which is then fed through a die to produce
the required size of pellet. Wood pellets do not require
any binding agent to be added as the lignin present in the cells
of the wood binds the material together when subjected to the
high temperatures and pressures found in the pellet mill.

Clifford Jones timber have recently commissioned
a Wood pellet mill in Wales (pictured). Using a biomass boiler
to produce the heat and power required for the production process,
the carbon impact of the plant is significantly reduced.

Due to processing and delivery operations biomass is not 100%
carbon neutral, however it is classed as being carbon neutral
as the emissions factors for biomass fuels are significantly
lower that that of fossil fuels for example:

A large house using 25,000kWh for heating:

Using mains Gas: 25000
x 0.194
= 4850Kg/CO2

Using Oil:
25000 x 0.27
= 6750Kg/CO2

Using Wood Pellets: 25000 x 0.025
= 625Kg/CO2

Wood Pellets produce 10.8 times less CO2 than Oil
And 7.76 times less CO2 than Mains Gas
Wood Pellets would have to be transported at least 3000km by
lorry before they have the same CO2 emissions per tonne as mains
gas.

What
kind of system will I require?

Biomass fuels can be used
in various types of appliance, ranging from a basic wood burning
stove to a combined heat and power plant producing 2 MWel, for
example. There are several types of boiler design available,
each suited to specific applications. For instance smaller
domestic boilers are likely to be either manually fed, such as
log gasification boilers which require fuel to be loaded and
ignited by hand for each batch of fuel. Automatic feed
systems which are available for wood pellet boilers which will
ignite/extinguish and modulate their output without input from
the user. The boiler designs for larger output boilers
are usually less compact and will accept less homogenous fuels
such as wood chip, waste such as forest residues, seeds and grain
and combinations of biomass fuels. The larger output stepped
grate and fluidised bed combustion boilers are not usually economically
viable below 500kWth, unless there is a constant demand for heat,
such as an industrial process. The initial capital outlay
of all biomass systems is a major influence on the selection
of type of plant to be installed. The balance between the
initial cost and the payback time of a system may make a certain
type of biomass system uneconomical.

The space required for fuel storage as well as space for a delivery
vehicle access to the fuel store must also be considered when
planning a biomass installation. In the domestic market many
properties currently on oil will already have their fuel stored
on site and will have access for delivery vehicles, conversely
a property with a mains gas supply in an urban environment may
not have the space required to install a biomass system.
In the urban setting district or community heating may be more
appropriate. This solution may use a large biomass boiler
or a combination of heat recovery, from an industrial process,
and biomass to provide heating for a number of properties.
This scale installation also lends its self to combined heat
and power (C.H.P) installations which provide both heating and
electrical power.

Smaller
appliances for use in the domestic setting are usually fired
from high quality wood fuels. The higher energy densities
of wood fuels such as wood pellets, when compared to bagasse
pellets for example, are more suited to the domestic setting
as they require a low volume of storage. The low levels
of ash produced from modern high efficiency boilers reduce the
amount of cleaning required and allow compact boiler designs
to be produced. The homogenous nature of wood pellets allows
ease of handling and delivery to the customer. Wood fuels
are non-volatile, non toxic and present few hazards to the user
or distributor. The end-user experience of wood pellet
appliances is potentially much like that of a gas or oil boiler
as automatic fuel feed, ash cleaning and removal are available
on boilers such as the Windhager BioWIN Automatic wood pellet
boiler (pictured).

How
can I source Biomass fuels?

Biomass fuels should be sourced as locally as possible, for example
it is not good practice to switch from oil or gas in the UK and
then source fuel from South America, for instance. The
prevalence of timber processing as well as managed forests make
woody biomass is the obvious choice for use as a renewable fuel
within the UK. Logs can be sourced from local timber suppliers,
from your own woodland or as a by product of your job or business.
Wood pellet mills and suppliers are increasing in number each
year, currently there are at least 13 mills currently operational
in the UK with various companies supplying either UK pellets
or foreign manufactured pellets. The market for wood pellets
in the UK is currently expanding, the instability of oil prices
has helped to stimulate market growth. The indexing of
the price of pellets to the price oil undermines wood pellet's
selling point as being a stable priced, better value alternative
to oil. As the market develops, pellets and other biomass
fuels should be traded as commodities in their own right as they
can be sourced from local supplies and do not require large amounts
of fossil fuels to produce or deliver them to the end user.

Bronzeoak -leader in the development of biomass
projects - Bronzeoak finances and owns renewable energy projects
and is working on sustainable developments in the UK, the Philippines,
Indonesia, Malaysia and Vietnam.

Dunster - a leading UK installer of district
heating systems, ETA wood chip, pellet and log boilers. Based
at Bathealton, near Taunton, they design, install and maintain
biomass heating.